snatch block vs fairlead

snatch block and fairlead both are nouns.

Word	Noun	Adjective	Verb	Adverb
snatch block	Yes	No	No	No
fairlead	Yes	No	No	No

As nouns, fairlead is a hypernym of snatch block; that is, fairlead is a word with a broader meaning than snatch block:

snatch block: a pulley-block that can be opened to receive the bight of a rope
fairlead: a pulley-block used to guide a rope forming part of a ship's rigging to avoid chafing

snatch block (noun)	fairlead (noun)
a pulley-block that can be opened to receive the bight of a rope	a pulley-block used to guide a rope forming part of a ship's rigging to avoid chafing